Bamboo is a prolific woody grass that has long been used in various forms as a construction material. Bamboo possesses numerous properties advantageous to the construction industry. Of particular utility is the high vertical compression strength when used in pole form, also referred to as bamboo cane, as a vertical support member or load bearing element in a structure.
Traditional western construction practices utilize materials having well defined standardized dimensions, durability and strength characteristics. Consequently the use of bamboo cane, in its natural form as a replacement for traditional lumber, has been limited by inconsistency of cane sizes and structural variations requiring parsing and selection for diameter, length and wall thickness to satisfy structural specifications for each application. Additionally, the inconsistent shapes and dimensions of bamboo cane are difficult and costly to incorporate in the construction of most traditional buildings. Consequently, other methods of using bamboo present in the prior art are principally directed towards utilizing bamboo to replace wood in composite materials such as plywood, panels, or boards wherein the bamboo is shredded, cut into strips, wafers, or chips typically having the size and shape of the equivalent wood material. The portion of the bamboo that most closely mimics the equivalent wood material is the cellulose fibers and vascular components present in the outer portions of the bamboo culm where the density of the fibers and vascular components are high relative to a surrounding lignin natural polymer binder. Typically, the outer third portion of the culm is harvested, discarding the remainder, and shredded or crushed into wafers, chips, strands, flakes or other small shapes that are, in turn, bound together with resins and formed into board such as oriented strand board (OSB). These processes permit manufacturing finished construction materials utilizing bamboo and having consistent and predictable dimensions and structural characteristics. Composite products formed in this matter necessarily break the lignin natural bonding material and then are re-bonded with resin consequently losing a significant portion of the structural characteristics of a bamboo cane. In particular, breaking the natural lignin polymer bonds and re-bonding with resin significantly adds to the weight and cost of the finished material as compared to the weight and cost of the equivalent volume of raw bamboo. Further, the natural high vertical compression strength structure of the bamboo cane is lost.
Utilizing bamboo as a replacement for wood in load bearing construction materials has been problematic. However, bamboo has many advantages over wood as a raw material. Bamboo is generally lower cost than wood. Bamboo is fast growing requiring only 3 to 4 years before harvesting as timber grade bamboo, a growth time significantly less than wood. As compared to wood, bamboo has a higher rot resistance and resistance to insect infestation than most woods. Further, bamboo has a higher level of carbon sequestration than most woods. Therefore, what is needed is an improved load bearing construction material principally utilizing bamboo while maintaining the bamboo culm structure largely in tact thereby capitalizing on the advantageous characteristics of bamboo timber while providing a material with substantially consistent and predictable dimensions and structural characteristics such as timber or other load bearing structural components.